Understanding memory use in top
by RandomTroll from LinuxQuestions.org on (#55H0F)
I don't understand the memory usage from this top display. This is sorted by memory use. I show all tasks that use more than 0%. They use less than 20% total, yet 90% of memory is in use and some of the swap drive! There are only 254 tasks, so even if they really use .1% that's only an additional 23%. And why is any swap being used when there's more memory than that free?
Code:top - 17:58:40 up 467 days, 7:41, 1 user, load average: 0.60, 0.28, 0.18
Tasks: 254 total, 1 running, 251 sleeping, 0 stopped, 2 zombie
Cpu(s): 2.9%us, 1.9%sy, 0.1%ni, 92.5%id, 0.9%wa, 0.0%hi, 0.2%si, 1.6%st
Mem: 4053604k total, 3628684k used, 424920k free, 1090624k buffers
Swap: 4194300k total, 279332k used, 3914968k free, 1339120k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
321 mysql 20 0 3177m 244m 6260 S 0.0 6.2 792:44.38 mysqld
23896 nobody 20 0 1958m 40m 10m S 0.7 1.0 1:30.79 httpd
30163 nobody 20 0 1958m 40m 10m S 0.3 1.0 1:22.88 httpd
2937 nobody 20 0 1958m 40m 10m S 0.0 1.0 1:12.33 httpd
4812 nobody 20 0 1958m 40m 10m S 0.0 1.0 1:14.47 httpd
2740 nobody 20 0 1958m 40m 10m S 0.3 1.0 1:16.22 httpd
2704 root 20 0 111m 25m 6876 S 4.0 0.7 296:56.18 cpsrvd (SSL) -
19801 root 20 0 235m 25m 6584 S 0.0 0.6 0:51.98 httpd
23438 nobody 20 0 235m 18m 472 S 0.0 0.5 0:02.49 httpd
22593 root 20 0 120m 16m 1512 S 0.0 0.4 0:02.45 bash
6374 named 20 0 697m 13m 1348 S 0.0 0.3 12:45.68 named
2763 root 20 0 57816 9904 1404 S 0.3 0.2 114:01.62 cPhulkd - proce
1349 root 20 0 48572 8036 1888 S 0.3 0.2 33:59.77 cPhulkd - dbpro
2982 root 20 0 56780 5760 1732 S 0.0 0.1 1:52.71 tailwatchd
2710 root 20 0 44668 5288 1436 S 0.0 0.1 43:40.28 queueprocd - wa
25684 root 20 0 220m 5280 564 S 0.0 0.1 280:47.02 rsyslogd
22265 root 20 0 102m 4532 3428 S 0.0 0.1 0:00.05 sshd
23861 dovecot 22 2 66580 4256 3156 S 0.0 0.1 0:00.01 auth
23970 root 22 2 66480 3972 2972 S 0.0 0.1 0:00.01 auth
32144 dovenull 22 2 47816 3912 1900 S 0.0 0.1 2:23.49 imap-login
32150 dovenull 22 2 47152 3492 1896 S 0.0 0.1 0:51.14 imap-login
32147 dovenull 22 2 46772 3356 1816 S 0.0 0.1 0:15.75 pop3-login
2778 root 20 0 25520 3276 2164 S 0.0 0.1 7:47.88 cpdavd - accept
32143 dovenull 22 2 46368 3104 1892 S 0.0 0.1 0:07.83 pop3-login
2715 root 20 0 24976 2596 1836 S 0.0 0.1 17:53.01 dnsadmin - dorm
7643 root 22 2 30420 2224 1796 S 0.0 0.1 0:00.00 quota-status
Code:top - 17:58:40 up 467 days, 7:41, 1 user, load average: 0.60, 0.28, 0.18
Tasks: 254 total, 1 running, 251 sleeping, 0 stopped, 2 zombie
Cpu(s): 2.9%us, 1.9%sy, 0.1%ni, 92.5%id, 0.9%wa, 0.0%hi, 0.2%si, 1.6%st
Mem: 4053604k total, 3628684k used, 424920k free, 1090624k buffers
Swap: 4194300k total, 279332k used, 3914968k free, 1339120k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
321 mysql 20 0 3177m 244m 6260 S 0.0 6.2 792:44.38 mysqld
23896 nobody 20 0 1958m 40m 10m S 0.7 1.0 1:30.79 httpd
30163 nobody 20 0 1958m 40m 10m S 0.3 1.0 1:22.88 httpd
2937 nobody 20 0 1958m 40m 10m S 0.0 1.0 1:12.33 httpd
4812 nobody 20 0 1958m 40m 10m S 0.0 1.0 1:14.47 httpd
2740 nobody 20 0 1958m 40m 10m S 0.3 1.0 1:16.22 httpd
2704 root 20 0 111m 25m 6876 S 4.0 0.7 296:56.18 cpsrvd (SSL) -
19801 root 20 0 235m 25m 6584 S 0.0 0.6 0:51.98 httpd
23438 nobody 20 0 235m 18m 472 S 0.0 0.5 0:02.49 httpd
22593 root 20 0 120m 16m 1512 S 0.0 0.4 0:02.45 bash
6374 named 20 0 697m 13m 1348 S 0.0 0.3 12:45.68 named
2763 root 20 0 57816 9904 1404 S 0.3 0.2 114:01.62 cPhulkd - proce
1349 root 20 0 48572 8036 1888 S 0.3 0.2 33:59.77 cPhulkd - dbpro
2982 root 20 0 56780 5760 1732 S 0.0 0.1 1:52.71 tailwatchd
2710 root 20 0 44668 5288 1436 S 0.0 0.1 43:40.28 queueprocd - wa
25684 root 20 0 220m 5280 564 S 0.0 0.1 280:47.02 rsyslogd
22265 root 20 0 102m 4532 3428 S 0.0 0.1 0:00.05 sshd
23861 dovecot 22 2 66580 4256 3156 S 0.0 0.1 0:00.01 auth
23970 root 22 2 66480 3972 2972 S 0.0 0.1 0:00.01 auth
32144 dovenull 22 2 47816 3912 1900 S 0.0 0.1 2:23.49 imap-login
32150 dovenull 22 2 47152 3492 1896 S 0.0 0.1 0:51.14 imap-login
32147 dovenull 22 2 46772 3356 1816 S 0.0 0.1 0:15.75 pop3-login
2778 root 20 0 25520 3276 2164 S 0.0 0.1 7:47.88 cpdavd - accept
32143 dovenull 22 2 46368 3104 1892 S 0.0 0.1 0:07.83 pop3-login
2715 root 20 0 24976 2596 1836 S 0.0 0.1 17:53.01 dnsadmin - dorm
7643 root 22 2 30420 2224 1796 S 0.0 0.1 0:00.00 quota-status